LOL - My bedroom is always HOT

[DougandLiz]

I've got a three-story townhouse with the thermostat on the middle floor. The top-floor, front-facing bedroom is always HOT (5-10 degrees warmer than the 2nd floor rooms).

I'm going to be getting a new system - either the Carrier 2-speed Infinity 25HNA6 or the Carrier 1-speed Performance 25HPA524.

Will the 2-speed help cool my top-floor bedroom or will it actually make the situation worse? And the 2-speed doesn't have a scroll compressor. It has a recprocating compressor. Am I better off going with the 1-speed with the scroll compressor then?

Please advise...

DougandLiz

[mark beiser]

New equipment won't make your duct system distribute the air any more evenly than it is now.
The duct system needs to be fixed.

[DougandLiz]

Hi Mark - Thanks for the reply. I know you're right about the duct work, but my heat pump died, so I've got to replace it anyway and I don't want to make a bad situation worse. Is the 2-speed non-scroll system worth the extra cost?

Thx,

DougandLiz

[Twilly]

Where is Weber?

[pateman29]

Yeh, it sounds like the installer didn't get the duct calculations right. D you know what size line is in the bedroom that is getting to hot,And the duct sizes of other rooms in the house? Where is the unit located?

[pateman29]

scroll compressors replace about 15 components in a typical piston type compressor.they require no valves which makers them10% more efficent than a reciprocating compressor.They can also be started under any load condition with out a special start kit.they also have a higher tolerance to liquid refrigerent.Compliant scroll compressors can handle debris without being damaged.

[cmajerus]

the infinity would have a variable speed blower, which will help overcome SLIGHT duct design flaws, I would not install anything without the VS blower in any home I ever own in the future. The 2 speed unit will run longer cycles giving the airflow more time to even out the temps in the home, may help, can't hurt, look into the possibility's of reworking the upstairs ducting(most likely very hard) but anything is possible, the installing contractor can let you know .

[cmajerus]

scroll compressors replace about 15 components in a typical piston type compressor.they require no valves which makers them10% more efficent than a reciprocating compressor.They can also be started under any load condition with out a special start kit.they also have a higher tolerance to liquid refrigerent.Compliant scroll compressors can handle debris without being damaged.
get that right off the compressor manufacturers website:D:D Neglect will kill any compressor! A 2 stage system is more efficient than a 1 stage period, scroll or no scroll.
The size of your A/C is based on worst case cooling load. You don't need that much every day of the season. (Well maybe in Texas!!)

[DougandLiz]

I have a 30 year-old townhouse. I don't know the size of the ducts but the other rooms on the top floor are also somewhat warm - but don't get as much sun.

I need to replace my existing unit anyway and am concerned that a 2-cycle system may make the situation worse since it may stay on the lower cycle more often, no?

Also, as I understand things, a scroll compressor (which the single cycle has) is better than a reciprocating compressor (which the 2 cycle has), correct? So, I'm trying to figure out if the 2 cycle is worth the extra money.

The house also has humidity problems so I am leaning toward the 2 cycle, but would like to hear the opinions out there since my knowledge is so limited.

[cmajerus]

I have a 30 year-old townhouse. I don't know the size of the ducts but the other rooms on the top floor are also somewhat warm - but don't get as much sun.

I need to replace my existing unit anyway and am concerned that a 2-cycle system may make the situation worse since it may stay on the lower cycle more often, no?

Also, as I understand things, a scroll compressor (which the single cycle has) is better than a reciprocating compressor (which the 2 cycle has), correct? So, I'm trying to figure out if the 2 cycle is worth the extra money.

The house also has humidity problems so I am leaning toward the 2 cycle, but would like to hear the opinions out there since my knowledge is so limited. It doesn't really matter, which is better they both have an extremely good warranty, and are very reliable, if the recip was so bad it wouldn't be used anymore.... If the scroll was the best for all applications then carrier would use it in all their equip.

The longer run cycles from only running at the lower speed should improve it, definitely shouldn't make it worse.

[adrianf]

Comfort; comfort and control.
1. Will the dual capacity save on utilities to give a 3 to 5 year payback. That's simple math that you and your dealer can do but has nothing to do with comfort or reliability.

2. Is the dual capacity capable of correcting design deficiencies? No.

3. Should the scroll compressor be the only compressor (dual or single capacity) unit I consider? No.

4. Can a single capacity unit coupled with proper duct design and installation deliver comfort and energy savings. Si

5. Is a home with 3 living levels a good match to a single control point? Probably not.

There has got to be a competent qualified contractor near you.

[tinner73]

if you have humidity issues the equipment may be over sized.

[pateman29]

no i just memerize most things that i was taught. No compressor can take neglect,never said that.Never said to get a scroll compressor either.Just give some advice for a scroll vs reciprocating compressor.

[udarrell]

Find some competent source to do an energy analysis of the third floor & in particular the hot room. Try contacting county government, university extensions & other "energy conservation sources," for an analysis.

Then using their analysis figure the payback on doing the retro work that will sufficiently reduce the radiant & other heatloads on those rooms so they will be closer to all the other rooms.

If at all possible & affordable, increase the size of the supply & return air ducts to those rooms. Install dampers near the plenum on all duct runs, then balance the airflow cfm for the Btuh each room requires.

I wish everyone had the money to do the retro work to correct all the problems the initial builders & installer's didn't do right. - Darrell

[Shophound]

A few things:


Due diligence as to why your old system died. If it was an airflow related problem, it may contribute to trouble with your new system
Load calculation to determine the air flow requirements for each room in the townhouse. Such analysis would likely find the existing airflow to the hot bedroom is inadequate for design day heat gain levels
One system cooling/heating three levels of living space will always present obstacles for evenly conditioning these levels
Existing ductwork may be leaky and/or restrictive, depriving hot bedroom of needed airflow
Investigate ways to reduce heat gain to hot bedroom, such as exterior or interior shading of exposed windows, and increased attic insulation/radiant barrier (since hot bedroom is on top level adjacent to attic). If supply vent to hot bedroom is in ceiling and there is attic above that ceiling, consider removing supply air grill and sealing gap between ceiling drywall and metal duct boot. This may not seem significant, but if the gap is significant, you are blowing cool air into the attic, where it is wasted
High humidity levels in summer sometimes may mean an oversized system, but not always. If the structure leaks in a significant amount of outdoor air, indoor humidity levels will be difficult to control, even with a properly sized system. If indoor humidity levels tend to run on the dry side in winter, this is also a strong sign the townhouse is leaky.